I don't know much about knappng, but these tools you guys are
posting look as though they could be made in a matter of minutes.
Easy come, easy go?
So I'm wondering if they were meant to be used over and over to the extent that they would show much wear.
To answer my own question, I suppose that if they were carried long distances to places where there were no materials for toolmaking, their value would be greater and they would be retained for further use.
These would be the "gems" mentioned by Cognito:
and a few gems. Pack up the nice stuff, leave the rest of the crap and boogie. You may drop a few of the gems on the way or just put one down and never pick it up. We generally find the left-behind stuff or the broken tools. The true gems are rare.
So...to follow up on Min's suggestion, it seems that the "gems" are probably the ones that were actually used, and probably repeatedly (if not broken), and that those are the ones that would most likely show the signs of the aforementioned use.
I recall seeing micorophotos of blades which supposedly indicated the type of material they were used to cut or scrape...bone, hide, wood,
fibrous plants, etc.
The deeper you go, the higher you fly.